#!/usr/bin/yabasic
REM Program Name: cbm-mtudemo.yab
REM Author: mtu
REM
REM Purpose: demonstration for their CBM-PET graphics card 320x200

open window 320, 200

20 P=160: Q=100
30 XP=144: XR=1.5*3.1415927
40 YP=56: YR=1: ZP=64
50 XF=XR/XP: YF=YP/YR: ZF=XR/ZP
60 FOR ZI=-Q TO Q-l
70 IF ZI<-ZP OR ZI>ZP GOTO 150
80 ZT=ZI*XP/ZP: ZZ=ZI
90 XL=INT(0.5+SQRT(XP*XP-ZT*ZT))
100 FOR XI=-XL TO XL
110 XT=SQRT(XI*XI+ZT*ZT)*XF: XX=XI
120 YY=(SIN(XT)+0.4*SIN(3.0*XT))*YF
130 GOSUB 170
140 NEXT XI
150 NEXT ZI
160 PAUSE 10
END
170 X1=XX+ZZ+P
180 Y1=YY-ZZ+Q:Y1=199-Y1
190 LINE X1,Y1,X1,Y1-1
200 IF Y1=0 GOTO 220
210 CLEAR LINE X1,Y1+1,X1,199
220 RETURN